Abstract: An apparatus is disclosed for stimulating a sleeping infant, preferably only to the point of slight awakening of the infant, such that the infant's SNS respiratory activation tone is maintained, over a period of time such as days or weeks, in opposition to PNS expression. An enclosure includes a circuit having a power source, a user interface, and timing and random number generator functions for producing successive rest durations, stimulation durations, and stimulation intensities, all based on preset distribution curves with preset variances. At least one stimulating device such, as a mass reciprocally moved by a motor, is electrically interconnected with the circuit. Upon expiration of a rest duration, the stimulating device is activated for the stimulation duration at the stimulation intensity, and then deactivated for the next successive rest duration.